Methods of producing and isolating parasite eggs for treating an autoimmune or allergic disease in a human or animal have been disclosed. These methods are important because observational studies on a number of immunologic diseases resulting from a dysregulated mucosal immune system may be corrected by treatment with embryonated Trichuris suis eggs (TSO). Reported are beneficial results for rheumatoid arthritis, multiple sclerosis, asthma, psoriasis, some IgE mediated food allergies (e.g. peanut allergy), and inflammatory bowel disease also known as ulcerative colitis and Crohn's Disease. These maladies have a much higher incidence in developed countries than in under-developed countries where helminths infections are common. Thus, it has been postulated that the increased frequency of these immunologic diseases in developed countries may be attributed to the reduced incidence of infections with intestinal helminths. Generally in clinical trials, patients ingested 2500 viable TSO every 2 or 3 weeks for at least 12 weeks.
Clinical studies have been reported using TSO for the treatment of inflammatory bowel disease (both Crohn's disease and ulcerative colitis) and positive results were reported.
In one such study, a randomized, double blind, placebo-controlled trial included 54 patients with active colitis, defined by an Ulcerative Colitis Disease Activity Index of >4. Patients were randomly assigned to receive placebo or TSO. Patients received 2500 Trichuris suis ova or placebo orally at 2-week intervals for 12 weeks. The primary efficacy variable was improvement of the Disease Activity Index to >4. After 12 weeks of therapy, improvement according to the intent-to-treat principle occurred in 13 of 30 patients (43.3%) with TSO treatment compared with 4 of 24 patients (16.7%) given placebo (P=0.04). Improvement was also found with the Simple Index that was significant by week 6. The difference in the proportion of patients who achieved an Ulcerative Colitis Disease Activity Index of 0-1 was not significant. Treatment reportedly induced no side effects.
In another example, a clinical study was performed on patients with active Crohn's disease to determine the safety and possible efficacy of treatment with intestinal TSO. In this study, twenty-nine patients with active Crohn's disease, defined by a Crohn's disease activity index (CDAI)>220 were enrolled. All patients ingested 2500 live TSO every three weeks for 24 weeks, and their disease activity was monitored by CDAI. Remission was defined as a decrease in CDAI to less than 150 while a response was defined as a decrease in CDAI of greater than 100. At week 24, 23 patients (79.3%) responded (decrease in CDAI, 100 points or CDAI, 150) and 21/29 (72.4%) remitted (CDAI, 150). Mean CDAI of responders decreased 177.1 points below baseline. Analysis at week 12 yielded similar results. There were no adverse events. These findings also support the premise that natural exposure to TSO affords protection from immunological diseases like Crohn's disease.
In another exemplary study that has been reported, the safety and effects of TSO was examined for patients with multiple sclerosis (MS), a phase 1 Helminth-induced Immunomodulatory Therapy (HINT 1). In this study, five patients with newly diagnosed, treatment-naive relapsing-remitting multiple sclerosis (RRMS) received 2500 TSO orally every 2 weeks for 3 months in a baseline versus treatment control exploratory trial. The mean number of new gadolinium-enhancing magnetic resonance imaging (MRI) lesions (n-Gd+) fell from 6.6 at baseline to 2.0 at the end of TSO administration, and 2 months after TSO was discontinued, the mean number of n-Gd+ rose to 5.8. No significant adverse effects were observed. In preliminary immunological investigations, increases in the serum level of the cytokines IL-4 and IL-10 were noted in four of the five subjects. TSO was well tolerated in RRMS, and favorable trends were observed in exploratory MRI and immunological assessments.
Helminths are worm-like animals (whip worms) that can live in the intestine or elsewhere in the body. Helminths have been reported to influence the host's mucosal immune response to limit inflammation and induce regulatory immune cells and immune regulatory pathways in the host. Trichuris suis is a natural parasite of pigs that hatch in the gastrointestinal tract in of swine and embed in the colonic wall. The worms were gradually expelled from week 5 to 11. While embedded in the colonic wall of pigs the Trichuris suis expel eggs in the feces.
In humans, embryonated Trichuris suis ova (TSO) hatch in the gastrointestinal tract and the larvae colonize the colonic wall briefly, but do not establish an infection [Summers, et al. (2005b)]. After a single treatment with 2500 infective eggs a transitory upregulated Th2-response (e.g. IL-4, IL-5, IL-13) was measurable at 3 weeks in the ileocaecal lymph nodes, while a more prolonged Th2-response was found in the colon mucosa. However, unlike the pig, the Trichuris suis worms cannot access the bloodstream from the crypts during colonization of the human gastrointestinal tract, thus they are unable to mature. They die within 2-3 weeks and are fully digested without producing eggs. Therefore, there is no expansion of the infection in humans and there also is no danger infecting others.
Methods for the recovery of eggs from the intestines or feces of pigs have been developed. The finished embryonated TSO product is stored at room temperature in a storage solution containing standard food preservatives. The TSO can be frozen and remain viable upon thawing. Although there has been no systematic testing of the effect of desiccation upon TSO, in nature, the eggs are shed into the soil where they may be desiccated, but remain viable for as many as nine years.
Methods are known and available for the isolation of TSO using dilute sulfuric acid from either porcine intestines or fecal material as the starting material. In these methods, embryonation is accomplished using a dilute solution of sulfuric acid having a pH below 6.
Trichuris suis ova (TSO), have been tested for viability using in vitro and in vivo methods. The influence of pH, different chemical, physical, and biological factors have been investigated for effects on TSO hatching.
The metabolism of TSO is greatly reduced by freezing or desiccation. However, incubation of eggs with mucosal scrapings from the ileum, caecum, and colon for 24 hours at 38° C. significantly increased hatching. It has also been reported that Ascaris lumbricoides ova are destroyed quickly at temperatures above 51° C., but are unaffected by long exposures to temperatures 47° C. or less.